TAB handler

It places the caret into the next editable cell.

Author: slisson

editor-runtime/src/commonMain/kotlin/org/modelix/editor/CaretPositionPolicy.kt

@@ -37,15 +37,14 @@ data class CaretPositionPolicy(
             .mapNotNull { editor.resolveLayoutable(it) }
 
         val best = candidates
-            .sortedByDescending { it.cell.ancestors(true).any { isPropertyCell(it) } }
+            .sortedByDescending { it.cell.isTabTarget() }
             .sortedBy { it.cell.ancestors(true).filter { isAvoided(it) }.count() }
             .firstOrNull() ?: return null
 
         return CaretSelection(best, (best.cell.getSelectableText() ?: "").length)
     }
 
     private fun isAvoided(cell: Cell) = cell.data.cellReferences.intersect(avoidedCellRefs).isNotEmpty()
-    private fun isPropertyCell(cell: Cell) = cell.data.cellReferences.any { it is PropertyCellReference }
 }
 
 enum class CaretPositionType {

editor-runtime/src/commonMain/kotlin/org/modelix/editor/CaretSelection.kt

@@ -80,6 +80,15 @@ class CaretSelection(val layoutable: LayoutableCell, val start: Int, val end: In
                 createNextPreviousLineSelection(false, desiredXPosition ?: getAbsoluteX())
                     ?.let { editor.changeSelection(it) }
             }
+            KnownKeys.Tab -> {
+                val target = layoutable
+                    .getSiblingsInText(!event.modifiers.shift)
+                    .filterIsInstance<LayoutableCell>()
+                    .firstOrNull { it.cell.isTabTarget() }
+                if (target != null) {
+                    editor.changeSelection(CaretSelection(target, 0))
+                }
+            }
             KnownKeys.Delete, KnownKeys.Backspace -> {
                 if (start == end) {
                     val posToDelete = when (knownKey) {

editor-runtime/src/commonMain/kotlin/org/modelix/editor/CellProperties.kt

@@ -46,4 +46,7 @@ object CommonCellProperties {
     val placeholderTextColor = CellPropertyKey<String?>("placeholder-text-color", "lightGray", inherits = true)
     val backgroundColor = CellPropertyKey<String?>("background-color", null)
     val textReplacement = CellPropertyKey<String?>("text-replacement", null)
+    val tabTarget = CellPropertyKey<Boolean>("tab-target", false) // caret is placed into the cell when navigating via TAB
 }
+
+fun Cell.isTabTarget() = getProperty(CommonCellProperties.tabTarget)

editor-runtime/src/commonMain/kotlin/org/modelix/editor/CellTemplate.kt

@@ -248,6 +248,7 @@ open class PropertyCellTemplate<NodeT : ITypedNode, ConceptT : ITypedConcept>(co
         val value = node.getPropertyValue(property)
         val data = TextCellData(value ?: "", if (value == null) placeholderText else "")
         data.properties[CellActionProperties.replaceText] = ChangePropertyAction(node)
+        data.properties[CommonCellProperties.tabTarget] = true
         data.cellReferences += PropertyCellReference(property, node.untypedReference())
         return data
     }
@@ -303,9 +304,10 @@ class ReferenceCellTemplate<NodeT : ITypedNode, ConceptT : ITypedConcept, Target
     val presentation: TargetNodeT.() -> String?
 ) : CellTemplate<NodeT, ConceptT>(concept), IGrammarSymbol {
     override fun createCell(context: CellCreationContext, node: NodeT): CellData {
-        val cell = TextCellData(getText(node), "<no ${link.name}>")
-        cell.cellReferences += ReferencedNodeCellReference(node.untypedReference(), link)
-        return cell
+        val data = TextCellData(getText(node), "<no ${link.name}>")
+        data.cellReferences += ReferencedNodeCellReference(node.untypedReference(), link)
+        data.properties[CommonCellProperties.tabTarget] = true
+        return data
     }
     private fun getText(node: NodeT): String = getTargetNode(node)?.let(presentation) ?: ""
     private fun getTargetNode(sourceNode: NodeT): TargetNodeT? {
@@ -369,6 +371,7 @@ class ChildCellTemplate<NodeT : ITypedNode, ConceptT : ITypedConcept>(
             if (isDefaultPlaceholder) {
                 placeholder.cellReferences += ChildNodeCellReference(node.untypedReference(), link, index)
             }
+            placeholder.properties[CommonCellProperties.tabTarget] = true
             cell.addChild(placeholder)
         }
         val addInsertActionCell: (Int) -> Unit = { index ->